The present invention relates to a storage system used in a computer system. More particularly, the present invention relates to a method for extending the volume capacity when data is written from a host computer to a storage system.
In general, a computer system is composed of a host computer that performs operations and a storage system that reads and writes data according to instructions from the host computer. The storage system provides multiple volumes to and from which data is stored and read.
An increase in the amount of data written by a host computer requires an increase in the capacity of the volumes allocated to that host computer. This is called the extension of the volume capacity.
An example of the volume capacity extension method is that a storage administrator stops the operation of a host computer, extends the capacity, and restarts the operation of the host computer. The problem with this method is that the operation of the host computer must be once stopped and, therefore, the operation is interrupted.
U.S. Pat. No. 6,823,442 discloses a volume capacity automatic extension technology for use in a storage system. The volume capacity automatic extension technology is a technology in which a storage area pool is prepared in the storage system and a volume created from this storage area pool, which shows a virtual capacity to the host computer, is used to allocate a necessary storage area according to data written by the host computer.